Fog dispersion was plain to see

But it was the need to get off the ground in a hurry that spurred Rogue Valley aviators to experiment with what became known as cloud seeding.

The practice was pioneered in Medford by the late George Milligan— best known for founding the air ambulance company Mercy Flights — during the late 1950s and became a staple in keeping air traffic flowing.

Low-flying planes dropped dry ice pellets, which condensed moisture in the fog, allowing it to fall to the ground as rain or snow, and clearing the fog in the process.

Cloud seeding was invented by a meteorologist in New England and first used to increase precipitation. Milligan was a pioneer in using it to break up fog at airports.

Wayne Reavis, who flew on a couple hundred seeding missions, said propane was another option, "but a lot of people don't want a bunch of propane in their airplane."

In November 2009 the practice abruptly ended when FAA regulations made it too dangerous for pilots to perform the operation.